Shaft (civil engineering)

In civil engineering a shaft is an underground vertical or inclined passageway. Shafts are often entered through a manhole and closed by a manhole cover. They are constructed for a number of reasons including:

• For the construction of a tunnel
• For ventilation of a tunnel or underground structure, aka ventilation shaft
• As a drop shaft for a sewerage or water tunnel
• For access to a tunnel or underground structure, also as an escape route